In the production of coated optical fibers, a resin coating is provided for protection and reinforcement immediately after spinning molten glass fibers. A known structure of the resin coating consists of a primary coating layer of a relatively flexible resin which is coated on the surface of optical fibers and a secondary coating layer of a relatively rigid resin which is provided over the primary coating layer. A so-called optical fiber ribbon is composed of a plurality of these coated optical glass fibers, e.g., four or eight optical fibers, by arranging these fibers typically in a plane and fixing them with a binder material to produce a ribbon structure with a rectangular cross-section. The binder material for preparing the optical fiber ribbon from a plurality of optical fibers is called a ribbon matrix material. A structure composed of a plurality of these ribbons is often referred to as a bundle. The material for binding such a bundle of ribbons is called a bundling material.
In the manufacture of optical fiber ribbons and multiple ribbon bundles it is important that the ribbons and/or bundles manufactured are smoothly wound up and the wound ribbons and/or bundles can be smoothly drawn out at a specific rate to smoothly complete the manufacture of optical fiber cables and/or easily utilize the ribbons/bundles in succeeding steps. Conventionally, a lubricant such as silicone oil or a powder such as talc has been applied to the surface of the ribbon to provide a slippery surface, whereby smooth wind-up and draw-out operations of the optical fiber ribbons and/or bundles are ensured.
Another method to provide good surface slip characteristics is a method of adding an additive such as silicone oil to the ribbon matrix material or the bundling material. Although such additives improve the surface slip characteristics of the cured product, the use of silicone oil or other conventional additives, however, impairs the shelf-life of the composition. Specifically, the addition of a large amount of additives causes the liquid composition to separate into two layers during storage. If the amount of such an additive remains small so that the shelf-life of the compositions remain relatively unaffected, it is necessary to apply a powder such as talc when ribbons are produced, because the cured product does not have sufficient surface slip characteristics.